1 files changed, 372 insertions, 362 deletions
diff --git a/libxcb/src/xcb_out.c b/libxcb/src/xcb_out.c
index fbce7a0ea..4f27de116 100644
--- a/libxcb/src/xcb_out.c
+++ b/libxcb/src/xcb_out.c
@@ -1,362 +1,372 @@
-/* Copyright (C) 2001-2004 Bart Massey and Jamey Sharp.
- *
- * Permission is hereby granted, free of charge, to any person obtaining a
- * copy of this software and associated documentation files (the "Software"),
- * to deal in the Software without restriction, including without limitation
- * the rights to use, copy, modify, merge, publish, distribute, sublicense,
- * and/or sell copies of the Software, and to permit persons to whom the
- * Software is furnished to do so, subject to the following conditions:
- * 
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- * 
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
- * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
- * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
- * 
- * Except as contained in this notice, the names of the authors or their
- * institutions shall not be used in advertising or otherwise to promote the
- * sale, use or other dealings in this Software without prior written
- * authorization from the authors.
- */
-
-/* Stuff that sends stuff to the server. */
-
-#include <assert.h>
-#include <stdlib.h>
-#include <unistd.h>
-#include <string.h>
-
-#include "xcb.h"
-#include "xcbext.h"
-#include "xcbint.h"
-#include "bigreq.h"
-
-static int write_block(xcb_connection_t *c, struct iovec *vector, int count)
-{
-    while(count && c->out.queue_len + vector[0].iov_len <= sizeof(c->out.queue))
-    {
-        memcpy(c->out.queue + c->out.queue_len, vector[0].iov_base, vector[0].iov_len);
-        c->out.queue_len += vector[0].iov_len;
-        vector[0].iov_base = (char *) vector[0].iov_base + vector[0].iov_len;
-        vector[0].iov_len = 0;
-        ++vector, --count;
-    }
-    if(!count)
-        return 1;
-
-    --vector, ++count;
-    vector[0].iov_base = c->out.queue;
-    vector[0].iov_len = c->out.queue_len;
-    c->out.queue_len = 0;
-    return _xcb_out_send(c, vector, count);
-}
-
-static void get_socket_back(xcb_connection_t *c)
-{
-    while(c->out.return_socket && c->out.socket_moving)
-        pthread_cond_wait(&c->out.socket_cond, &c->iolock);
-    if(!c->out.return_socket)
-        return;
-
-    c->out.socket_moving = 1;
-    pthread_mutex_unlock(&c->iolock);
-    c->out.return_socket(c->out.socket_closure);
-    pthread_mutex_lock(&c->iolock);
-    c->out.socket_moving = 0;
-
-    pthread_cond_broadcast(&c->out.socket_cond);
-    c->out.return_socket = 0;
-    c->out.socket_closure = 0;
-    _xcb_in_replies_done(c);
-}
-
-/* Public interface */
-
-void xcb_prefetch_maximum_request_length(xcb_connection_t *c)
-{
-    if(c->has_error)
-        return;
-    pthread_mutex_lock(&c->out.reqlenlock);
-    if(c->out.maximum_request_length_tag == LAZY_NONE)
-    {
-        const xcb_query_extension_reply_t *ext;
-        ext = xcb_get_extension_data(c, &xcb_big_requests_id);
-        if(ext && ext->present)
-        {
-            c->out.maximum_request_length_tag = LAZY_COOKIE;
-            c->out.maximum_request_length.cookie = xcb_big_requests_enable(c);
-        }
-        else
-        {
-            c->out.maximum_request_length_tag = LAZY_FORCED;
-            c->out.maximum_request_length.value = c->setup->maximum_request_length;
-        }
-    }
-    pthread_mutex_unlock(&c->out.reqlenlock);
-}
-
-uint32_t xcb_get_maximum_request_length(xcb_connection_t *c)
-{
-    if(c->has_error)
-        return 0;
-    xcb_prefetch_maximum_request_length(c);
-    pthread_mutex_lock(&c->out.reqlenlock);
-    if(c->out.maximum_request_length_tag == LAZY_COOKIE)
-    {
-        xcb_big_requests_enable_reply_t *r = xcb_big_requests_enable_reply(c, c->out.maximum_request_length.cookie, 0);
-        c->out.maximum_request_length_tag = LAZY_FORCED;
-        if(r)
-        {
-            c->out.maximum_request_length.value = r->maximum_request_length;
-            free(r);
-        }
-        else
-            c->out.maximum_request_length.value = c->setup->maximum_request_length;
-    }
-    pthread_mutex_unlock(&c->out.reqlenlock);
-    return c->out.maximum_request_length.value;
-}
-
-unsigned int xcb_send_request(xcb_connection_t *c, int flags, struct iovec *vector, const xcb_protocol_request_t *req)
-{
-    static const union {
-        struct {
-            uint8_t major;
-            uint8_t pad;
-            uint16_t len;
-        } fields;
-        uint32_t packet;
-    } sync_req = { { /* GetInputFocus */ 43, 0, 1 } };
-    uint64_t request;
-    uint32_t prefix[3] = { 0 };
-    int veclen = req->count;
-    enum workarounds workaround = WORKAROUND_NONE;
-
-    if(c->has_error)
-        return 0;
-
-    assert(c != 0);
-    assert(vector != 0);
-    assert(req->count > 0);
-
-    if(!(flags & XCB_REQUEST_RAW))
-    {
-        static const char pad[3];
-        unsigned int i;
-        uint16_t shortlen = 0;
-        size_t longlen = 0;
-        assert(vector[0].iov_len >= 4);
-        /* set the major opcode, and the minor opcode for extensions */
-        if(req->ext)
-        {
-            const xcb_query_extension_reply_t *extension = xcb_get_extension_data(c, req->ext);
-            if(!(extension && extension->present))
-            {
-                _xcb_conn_shutdown(c);
-                return 0;
-            }
-            ((uint8_t *) vector[0].iov_base)[0] = extension->major_opcode;
-            ((uint8_t *) vector[0].iov_base)[1] = req->opcode;
-        }
-        else
-            ((uint8_t *) vector[0].iov_base)[0] = req->opcode;
-
-        /* put together the length field, possibly using BIGREQUESTS */
-        for(i = 0; i < req->count; ++i)
-        {
-            longlen += vector[i].iov_len;
-            if(!vector[i].iov_base)
-            {
-                vector[i].iov_base = (char *) pad;
-                assert(vector[i].iov_len <= sizeof(pad));
-            }
-        }
-        assert((longlen & 3) == 0);
-        longlen >>= 2;
-
-        if(longlen <= c->setup->maximum_request_length)
-        {
-            /* we don't need BIGREQUESTS. */
-            shortlen = longlen;
-            longlen = 0;
-        }
-        else if(longlen > xcb_get_maximum_request_length(c))
-        {
-            _xcb_conn_shutdown(c);
-            return 0; /* server can't take this; maybe need BIGREQUESTS? */
-        }
-
-        /* set the length field. */
-        ((uint16_t *) vector[0].iov_base)[1] = shortlen;
-        if(!shortlen)
-            prefix[2] = ++longlen;
-    }
-    flags &= ~XCB_REQUEST_RAW;
-
-    /* do we need to work around the X server bug described in glx.xml? */
-    /* XXX: GetFBConfigs won't use BIG-REQUESTS in any sane
-     * configuration, but that should be handled here anyway. */
-    if(req->ext && !req->isvoid && !strcmp(req->ext->name, "GLX") &&
-            ((req->opcode == 17 && ((uint32_t *) vector[0].iov_base)[1] == 0x10004) ||
-             req->opcode == 21))
-        workaround = WORKAROUND_GLX_GET_FB_CONFIGS_BUG;
-
-    /* get a sequence number and arrange for delivery. */
-    pthread_mutex_lock(&c->iolock);
-    /* wait for other writing threads to get out of my way. */
-    while(c->out.writing)
-        pthread_cond_wait(&c->out.cond, &c->iolock);
-    get_socket_back(c);
-
-    request = ++c->out.request;
-    /* send GetInputFocus (sync_req) when 64k-2 requests have been sent without
-     * a reply.
-     * Also send sync_req (could use NoOp) at 32-bit wrap to avoid having
-     * applications see sequence 0 as that is used to indicate
-     * an error in sending the request */
-    while((req->isvoid &&
-	c->out.request == c->in.request_expected + (1 << 16) - 1) ||
-       request == 0)
-    {
-        prefix[0] = sync_req.packet;
-        _xcb_in_expect_reply(c, request, WORKAROUND_NONE, XCB_REQUEST_DISCARD_REPLY);
-        c->in.request_expected = c->out.request;
-	request = ++c->out.request;
-    }
-
-    if(workaround != WORKAROUND_NONE || flags != 0)
-        _xcb_in_expect_reply(c, request, workaround, flags);
-    if(!req->isvoid)
-        c->in.request_expected = c->out.request;
-
-    if(prefix[0] || prefix[2])
-    {
-        --vector, ++veclen;
-        if(prefix[2])
-        {
-            prefix[1] = ((uint32_t *) vector[1].iov_base)[0];
-            vector[1].iov_base = (uint32_t *) vector[1].iov_base + 1;
-            vector[1].iov_len -= sizeof(uint32_t);
-        }
-        vector[0].iov_len = sizeof(uint32_t) * ((prefix[0] ? 1 : 0) + (prefix[2] ? 2 : 0));
-        vector[0].iov_base = prefix + !prefix[0];
-    }
-
-    if(!write_block(c, vector, veclen))
-    {
-        _xcb_conn_shutdown(c);
-        request = 0;
-    }
-    pthread_mutex_unlock(&c->iolock);
-    return request;
-}
-
-int xcb_take_socket(xcb_connection_t *c, void (*return_socket)(void *closure), void *closure, int flags, uint64_t *sent)
-{
-    int ret;
-    if(c->has_error)
-        return 0;
-    pthread_mutex_lock(&c->iolock);
-    get_socket_back(c);
-    ret = _xcb_out_flush_to(c, c->out.request);
-    if(ret)
-    {
-        c->out.return_socket = return_socket;
-        c->out.socket_closure = closure;
-        if(flags)
-            _xcb_in_expect_reply(c, c->out.request, WORKAROUND_EXTERNAL_SOCKET_OWNER, flags);
-        assert(c->out.request == c->out.request_written);
-        *sent = c->out.request;
-    }
-    pthread_mutex_unlock(&c->iolock);
-    return ret;
-}
-
-int xcb_writev(xcb_connection_t *c, struct iovec *vector, int count, uint64_t requests)
-{
-    int ret;
-    if(c->has_error)
-        return 0;
-    pthread_mutex_lock(&c->iolock);
-    c->out.request += requests;
-    ret = _xcb_out_send(c, vector, count);
-    pthread_mutex_unlock(&c->iolock);
-    return ret;
-}
-
-int xcb_flush(xcb_connection_t *c)
-{
-    int ret;
-    if(c->has_error)
-        return 0;
-    pthread_mutex_lock(&c->iolock);
-    ret = _xcb_out_flush_to(c, c->out.request);
-    pthread_mutex_unlock(&c->iolock);
-    return ret;
-}
-
-/* Private interface */
-
-int _xcb_out_init(_xcb_out *out)
-{
-    if(pthread_cond_init(&out->socket_cond, 0))
-        return 0;
-    out->return_socket = 0;
-    out->socket_closure = 0;
-    out->socket_moving = 0;
-
-    if(pthread_cond_init(&out->cond, 0))
-        return 0;
-    out->writing = 0;
-
-    out->queue_len = 0;
-
-    out->request = 0;
-    out->request_written = 0;
-
-    if(pthread_mutex_init(&out->reqlenlock, 0))
-        return 0;
-    out->maximum_request_length_tag = LAZY_NONE;
-
-    return 1;
-}
-
-void _xcb_out_destroy(_xcb_out *out)
-{
-    pthread_cond_destroy(&out->cond);
-    pthread_mutex_destroy(&out->reqlenlock);
-}
-
-int _xcb_out_send(xcb_connection_t *c, struct iovec *vector, int count)
-{
-    int ret = 1;
-    while(ret && count)
-        ret = _xcb_conn_wait(c, &c->out.cond, &vector, &count);
-    c->out.request_written = c->out.request;
-    pthread_cond_broadcast(&c->out.cond);
-    _xcb_in_wake_up_next_reader(c);
-    return ret;
-}
-
-int _xcb_out_flush_to(xcb_connection_t *c, uint64_t request)
-{
-    assert(XCB_SEQUENCE_COMPARE(request, <=, c->out.request));
-    if(XCB_SEQUENCE_COMPARE(c->out.request_written, >=, request))
-        return 1;
-    if(c->out.queue_len)
-    {
-        struct iovec vec;
-        vec.iov_base = c->out.queue;
-        vec.iov_len = c->out.queue_len;
-        c->out.queue_len = 0;
-        return _xcb_out_send(c, &vec, 1);
-    }
-    while(c->out.writing)
-        pthread_cond_wait(&c->out.cond, &c->iolock);
-    assert(XCB_SEQUENCE_COMPARE(c->out.request_written, >=, request));
-    return 1;
-}
+/* Copyright (C) 2001-2004 Bart Massey and Jamey Sharp.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ * 
+ * Except as contained in this notice, the names of the authors or their
+ * institutions shall not be used in advertising or otherwise to promote the
+ * sale, use or other dealings in this Software without prior written
+ * authorization from the authors.
+ */
+
+/* Stuff that sends stuff to the server. */
+
+#include <assert.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+
+#include "xcb.h"
+#include "xcbext.h"
+#include "xcbint.h"
+#include "bigreq.h"
+
+static inline void send_request(xcb_connection_t *c, int isvoid, enum workarounds workaround, int flags, struct iovec *vector, int count)
+{
+    if(c->has_error)
+        return;
+
+    ++c->out.request;
+    if(!isvoid)
+        c->in.request_expected = c->out.request;
+    if(workaround != WORKAROUND_NONE || flags != 0)
+        _xcb_in_expect_reply(c, c->out.request, workaround, flags);
+
+    while(count && c->out.queue_len + vector[0].iov_len <= sizeof(c->out.queue))
+    {
+        memcpy(c->out.queue + c->out.queue_len, vector[0].iov_base, vector[0].iov_len);
+        c->out.queue_len += vector[0].iov_len;
+        vector[0].iov_base = (char *) vector[0].iov_base + vector[0].iov_len;
+        vector[0].iov_len = 0;
+        ++vector, --count;
+    }
+    if(!count)
+        return;
+
+    --vector, ++count;
+    vector[0].iov_base = c->out.queue;
+    vector[0].iov_len = c->out.queue_len;
+    c->out.queue_len = 0;
+    _xcb_out_send(c, vector, count);
+}
+
+static void send_sync(xcb_connection_t *c)
+{
+    static const union {
+        struct {
+            uint8_t major;
+            uint8_t pad;
+            uint16_t len;
+        } fields;
+        uint32_t packet;
+    } sync_req = { { /* GetInputFocus */ 43, 0, 1 } };
+    struct iovec vector[2];
+    vector[1].iov_base = (char *) &sync_req;
+    vector[1].iov_len = sizeof(sync_req);
+    send_request(c, 0, WORKAROUND_NONE, XCB_REQUEST_DISCARD_REPLY, vector + 1, 1);
+}
+
+static void get_socket_back(xcb_connection_t *c)
+{
+    while(c->out.return_socket && c->out.socket_moving)
+        pthread_cond_wait(&c->out.socket_cond, &c->iolock);
+    if(!c->out.return_socket)
+        return;
+
+    c->out.socket_moving = 1;
+    pthread_mutex_unlock(&c->iolock);
+    c->out.return_socket(c->out.socket_closure);
+    pthread_mutex_lock(&c->iolock);
+    c->out.socket_moving = 0;
+
+    pthread_cond_broadcast(&c->out.socket_cond);
+    c->out.return_socket = 0;
+    c->out.socket_closure = 0;
+    _xcb_in_replies_done(c);
+}
+
+/* Public interface */
+
+void xcb_prefetch_maximum_request_length(xcb_connection_t *c)
+{
+    if(c->has_error)
+        return;
+    pthread_mutex_lock(&c->out.reqlenlock);
+    if(c->out.maximum_request_length_tag == LAZY_NONE)
+    {
+        const xcb_query_extension_reply_t *ext;
+        ext = xcb_get_extension_data(c, &xcb_big_requests_id);
+        if(ext && ext->present)
+        {
+            c->out.maximum_request_length_tag = LAZY_COOKIE;
+            c->out.maximum_request_length.cookie = xcb_big_requests_enable(c);
+        }
+        else
+        {
+            c->out.maximum_request_length_tag = LAZY_FORCED;
+            c->out.maximum_request_length.value = c->setup->maximum_request_length;
+        }
+    }
+    pthread_mutex_unlock(&c->out.reqlenlock);
+}
+
+uint32_t xcb_get_maximum_request_length(xcb_connection_t *c)
+{
+    if(c->has_error)
+        return 0;
+    xcb_prefetch_maximum_request_length(c);
+    pthread_mutex_lock(&c->out.reqlenlock);
+    if(c->out.maximum_request_length_tag == LAZY_COOKIE)
+    {
+        xcb_big_requests_enable_reply_t *r = xcb_big_requests_enable_reply(c, c->out.maximum_request_length.cookie, 0);
+        c->out.maximum_request_length_tag = LAZY_FORCED;
+        if(r)
+        {
+            c->out.maximum_request_length.value = r->maximum_request_length;
+            free(r);
+        }
+        else
+            c->out.maximum_request_length.value = c->setup->maximum_request_length;
+    }
+    pthread_mutex_unlock(&c->out.reqlenlock);
+    return c->out.maximum_request_length.value;
+}
+
+unsigned int xcb_send_request(xcb_connection_t *c, int flags, struct iovec *vector, const xcb_protocol_request_t *req)
+{
+    uint64_t request;
+    uint32_t prefix[2];
+    int veclen = req->count;
+    enum workarounds workaround = WORKAROUND_NONE;
+
+    if(c->has_error)
+        return 0;
+
+    assert(c != 0);
+    assert(vector != 0);
+    assert(req->count > 0);
+
+    if(!(flags & XCB_REQUEST_RAW))
+    {
+        static const char pad[3];
+        unsigned int i;
+        uint16_t shortlen = 0;
+        size_t longlen = 0;
+        assert(vector[0].iov_len >= 4);
+        /* set the major opcode, and the minor opcode for extensions */
+        if(req->ext)
+        {
+            const xcb_query_extension_reply_t *extension = xcb_get_extension_data(c, req->ext);
+            if(!(extension && extension->present))
+            {
+                _xcb_conn_shutdown(c);
+                return 0;
+            }
+            ((uint8_t *) vector[0].iov_base)[0] = extension->major_opcode;
+            ((uint8_t *) vector[0].iov_base)[1] = req->opcode;
+        }
+        else
+            ((uint8_t *) vector[0].iov_base)[0] = req->opcode;
+
+        /* put together the length field, possibly using BIGREQUESTS */
+        for(i = 0; i < req->count; ++i)
+        {
+            longlen += vector[i].iov_len;
+            if(!vector[i].iov_base)
+            {
+                vector[i].iov_base = (char *) pad;
+                assert(vector[i].iov_len <= sizeof(pad));
+            }
+        }
+        assert((longlen & 3) == 0);
+        longlen >>= 2;
+
+        if(longlen <= c->setup->maximum_request_length)
+        {
+            /* we don't need BIGREQUESTS. */
+            shortlen = longlen;
+            longlen = 0;
+        }
+        else if(longlen > xcb_get_maximum_request_length(c))
+        {
+            _xcb_conn_shutdown(c);
+            return 0; /* server can't take this; maybe need BIGREQUESTS? */
+        }
+
+        /* set the length field. */
+        ((uint16_t *) vector[0].iov_base)[1] = shortlen;
+        if(!shortlen)
+        {
+            prefix[0] = ((uint32_t *) vector[0].iov_base)[0];
+            prefix[1] = ++longlen;
+            vector[0].iov_base = (uint32_t *) vector[0].iov_base + 1;
+            vector[0].iov_len -= sizeof(uint32_t);
+            --vector, ++veclen;
+            vector[0].iov_base = prefix;
+            vector[0].iov_len = sizeof(prefix);
+        }
+    }
+    flags &= ~XCB_REQUEST_RAW;
+
+    /* do we need to work around the X server bug described in glx.xml? */
+    /* XXX: GetFBConfigs won't use BIG-REQUESTS in any sane
+     * configuration, but that should be handled here anyway. */
+    if(req->ext && !req->isvoid && !strcmp(req->ext->name, "GLX") &&
+            ((req->opcode == 17 && ((uint32_t *) vector[0].iov_base)[1] == 0x10004) ||
+             req->opcode == 21))
+        workaround = WORKAROUND_GLX_GET_FB_CONFIGS_BUG;
+
+    /* get a sequence number and arrange for delivery. */
+    pthread_mutex_lock(&c->iolock);
+    /* wait for other writing threads to get out of my way. */
+    while(c->out.writing)
+        pthread_cond_wait(&c->out.cond, &c->iolock);
+    get_socket_back(c);
+
+    /* send GetInputFocus (sync_req) when 64k-2 requests have been sent without
+     * a reply. */
+    if(req->isvoid && c->out.request == c->in.request_expected + (1 << 16) - 2)
+        send_sync(c);
+    /* Also send sync_req (could use NoOp) at 32-bit wrap to avoid having
+     * applications see sequence 0 as that is used to indicate
+     * an error in sending the request */
+    if((unsigned int) (c->out.request + 1) == 0)
+        send_sync(c);
+
+    /* The above send_sync calls could drop the I/O lock, but this
+     * thread will still exclude any other thread that tries to write,
+     * so the sequence number postconditions still hold. */
+    send_request(c, req->isvoid, workaround, flags, vector, veclen);
+    request = c->has_error ? 0 : c->out.request;
+    pthread_mutex_unlock(&c->iolock);
+    return request;
+}
+
+int xcb_take_socket(xcb_connection_t *c, void (*return_socket)(void *closure), void *closure, int flags, uint64_t *sent)
+{
+    int ret;
+    if(c->has_error)
+        return 0;
+    pthread_mutex_lock(&c->iolock);
+    get_socket_back(c);
+    ret = _xcb_out_flush_to(c, c->out.request);
+    if(ret)
+    {
+        c->out.return_socket = return_socket;
+        c->out.socket_closure = closure;
+        if(flags)
+            _xcb_in_expect_reply(c, c->out.request, WORKAROUND_EXTERNAL_SOCKET_OWNER, flags);
+        assert(c->out.request == c->out.request_written);
+        *sent = c->out.request;
+    }
+    pthread_mutex_unlock(&c->iolock);
+    return ret;
+}
+
+int xcb_writev(xcb_connection_t *c, struct iovec *vector, int count, uint64_t requests)
+{
+    int ret;
+    if(c->has_error)
+        return 0;
+    pthread_mutex_lock(&c->iolock);
+    c->out.request += requests;
+    ret = _xcb_out_send(c, vector, count);
+    pthread_mutex_unlock(&c->iolock);
+    return ret;
+}
+
+int xcb_flush(xcb_connection_t *c)
+{
+    int ret;
+    if(c->has_error)
+        return 0;
+    pthread_mutex_lock(&c->iolock);
+    ret = _xcb_out_flush_to(c, c->out.request);
+    pthread_mutex_unlock(&c->iolock);
+    return ret;
+}
+
+/* Private interface */
+
+int _xcb_out_init(_xcb_out *out)
+{
+    if(pthread_cond_init(&out->socket_cond, 0))
+        return 0;
+    out->return_socket = 0;
+    out->socket_closure = 0;
+    out->socket_moving = 0;
+
+    if(pthread_cond_init(&out->cond, 0))
+        return 0;
+    out->writing = 0;
+
+    out->queue_len = 0;
+
+    out->request = 0;
+    out->request_written = 0;
+
+    if(pthread_mutex_init(&out->reqlenlock, 0))
+        return 0;
+    out->maximum_request_length_tag = LAZY_NONE;
+
+    return 1;
+}
+
+void _xcb_out_destroy(_xcb_out *out)
+{
+    pthread_cond_destroy(&out->cond);
+    pthread_mutex_destroy(&out->reqlenlock);
+}
+
+int _xcb_out_send(xcb_connection_t *c, struct iovec *vector, int count)
+{
+    int ret = 1;
+    while(ret && count)
+        ret = _xcb_conn_wait(c, &c->out.cond, &vector, &count);
+    c->out.request_written = c->out.request;
+    pthread_cond_broadcast(&c->out.cond);
+    _xcb_in_wake_up_next_reader(c);
+    return ret;
+}
+
+void _xcb_out_send_sync(xcb_connection_t *c)
+{
+    /* wait for other writing threads to get out of my way. */
+    while(c->out.writing)
+        pthread_cond_wait(&c->out.cond, &c->iolock);
+    get_socket_back(c);
+    send_sync(c);
+}
+
+int _xcb_out_flush_to(xcb_connection_t *c, uint64_t request)
+{
+    assert(XCB_SEQUENCE_COMPARE(request, <=, c->out.request));
+    if(XCB_SEQUENCE_COMPARE(c->out.request_written, >=, request))
+        return 1;
+    if(c->out.queue_len)
+    {
+        struct iovec vec;
+        vec.iov_base = c->out.queue;
+        vec.iov_len = c->out.queue_len;
+        c->out.queue_len = 0;
+        return _xcb_out_send(c, &vec, 1);
+    }
+    while(c->out.writing)
+        pthread_cond_wait(&c->out.cond, &c->iolock);
+    assert(XCB_SEQUENCE_COMPARE(c->out.request_written, >=, request));
+    return 1;
+}